By Tyler Cochran

An NMR or nuclear Magnetic Resonance Machine is used for chemical analysis and viewing the chemical makeup of different compounds. They are incredibly useful, and I use them multiple times a day in my organic synthesis lab. The MRI machine or Magnetic Resonance Imagining is found in most medical settings. It is used to image different tissue types. I think most people have had an MRI in their life and it has become widely used in the American Healthcare system. These machines are used for very different purposes yet have a lot of similarities, but also a couple of key differences.

These machines are a lot more similar than they are different. They both use big magnets and radio waves to visualize protons. Both machines would have the same name if it was not for the stigma around the word nuclear when the MRI was brought into the medical setting. The MRI uses its large magnets to excite the protons found in body tissue, as these protons transition lower from their excited state they release energy that is picked up by the MRI machine. The difference in energy given off and the time it takes these protons to lower their energy is interpreted by the machine and shows off the different types of tissues in the body. This 3D image is incredibly useful in diagnosing and visualizing the human body. The NMR uses the same technique to view protons in certain molecules. These protons release different amounts of energy and time based on what they are attached to. These chemical shifts can be interpreted and used to see what the compound in the solvent is. This has been useful in my lab. I work to make new benzoic acid derivatives and NMR helps me to look and see if I got my intended product and the purity of said product.

The biggest difference is the most obvious one, the size. NMR machines are built to look at nothing larger than a molecule, and they do an excellent job at that. MRI machines need to look at full bodies. Their scale is massive compared to an NMR machine and that changes how they need to work. The NMR machine gets more of its information from the frequency the proton returns to its low energy state. This is then shown along the x-axis of a graph that can be used to determine the molecule and what the hydrogen is attached to. The MRI machine measures the intensities that these protons give off and that allows them to differentiate the tissues and densities. These key differences allow both machines to be very good at what they do. They are both super useful but used for different things. Another big difference is the price of these machines. NMR machines come in a lot of different sizes, but the 400 MHz one in our lab costs around 300 thousand dollars. These can get upscaled though and can cost over a million dollars. Most MRI machines are anywhere from 1-3 million dollars. This is significantly more expensive than most commercial NMR machines are.